Conventionally, cleaning agents to be used for lavaging the alimentary canal conducted as a pre-treatment of alimentary canal radiographic inspection, alimentary canal endoscopy, alimentary canal operation, and the like have been known. As to said cleaning agents for lavaging the alimentary canal, for example, those comprising a combination of polyethylene glycol (PEG) and electrolyte (see, for example, JP-A-63-500523, JP-A-I-125319, JP-A-I-132527, JP-A-2-292223 (specification of U.S. Pat. No. 5,124,144)), those comprising a combination of at least one type of water-soluble macromolecule selected from polyethylene glycol, dextran, dextrin, hydroxyethyl starch, polydextrose, gum arabic and pectin and electrolyte (see, for example, JP-A-2-25424 (specification of U.S. Pat. No. 5,077,048) and JP-A-3-206046), and those comprising a combination of erythritol and/or xylitol and electrolyte (see, for example, JP-A-3-284620) have been known.
These conventional cleaning agents for lavaging the alimentary canal are usually required to be taken in an amount of 2-4 L (2-4×10−3 m3) in the time of its use, and have a drawback of unfavorable taste to be taken in sufficient amount, and further, since patients are forced to have a distress such as nausea after administration, etc. Accordingly, said cleaning agents have problems in common use.